Total ionization cross sections of Cl and Cl₂ by electron impact

Abstract

Cross sections of Cl and Cl 2 for ionization by electron impact are calculated using the Binary-EncounterBethe (BEB) theoretical model. The BEB model requires only the binding energies and kinetic energies of atomic or molecular orbitals (MO). For the lowest binding energies, experimental vertical ionization potentials (IPs) are used to make the theoretical ionization threshold coincide with the experimental threshold. Experimental cross sections, and cross sections calculated using alternative theoretical models, where available, are compared with the BEB results. The BEB cross sections agree well with the experimental data for Cl and Cl 2 .

Ionization cross sections by electron impact on halogen atoms, diatomic halogen and hydrogen halide molecules

“…We compare cross sections from ECP and BEB calculations for the present molecules. We previously reported BEB calculations for Cl and Cl 2 [9]. The excellent agreement between BEB cross sections and experimental results for Cl and Cl 2 supports the use of the ad hoc factor m in (1) for other systems under consideration.…”

“…BEB results in [9]. We use the Stuttgart RECPs [45,46] and the corresponding basis sets for the heavy atoms implemented as options in the Gaussian 03 software [47].…”

“…In the present paper, we employ the binary-encounter-Bethe (BEB) model of Kim and Rudd [8] to calculate direct ionization cross sections by electron impact for Br, I, Br 2 , I 2 , HCl, HBr and HI, extending our previous work on Cl and Cl 2 [9], and compare these with available experimental and theoretical results. The cross sections provided here are needed especially in computer models to determine temperatures, densities and dominant ions of the plasmas.…”

Decomposition of Carbon Tetrachloride on Gold Surfaces

“…Indeed, I + is proportional to the number of neutral targets ( N I ), ionization cross section (σ I + ), as well as the number of colliding 70 eV electrons ( N e ) and the ion-detection efficiency in the mass spectrometer (ε) via: I + = N I ·N e ·σ I+ ·ε. The ionization cross sections for Cl 2 + and the Cl + anion are 3.64 × 10 –20 (ref ) and 7 × 10 –20 m 2 (ref ), respectively, for 70 eV electrons. Assuming the same detection efficiency and bombardment electron density by the mass spectrometer for both the ions, the value of N C l2 /N CCl 4 is estimated to about 25%, from the slope of Figure weighted by the cross section σ I + .…”

Simulation of a QMS Including the Effects of Pressure in the Electron-Impact Ion Source

“…3) Ionization Cross Section Q i : The total ionization cross section in the ionic current expression can be calculated using the BEB theory [30]- [32]. The total ionization cross section can be obtained by integrating the differential cross section over the electron energy.…”